There is a cutting tool formed of a cBN sintered body as a base member having a surface on which a coating film made of ceramics or the like is formed (which will be hereinafter also referred to as a “coated cBN tool”). This cutting tool exhibits excellent wear resistance, and therefore, is used for cutting processing of hardened steel.
As such a cutting tool, for example, WO2010/150335 (PTD 1) and WO2012/005275 (PTD 2) each disclose a tool formed of a cBN sintered body having a surface coated with a coating film including a lower layer formed of multiple layers having specific ceramic compositions and an upper layer formed of a compound layer.
Furthermore, a base member of a tool having a coating film is formed not only of a cBN sintered body, for example, but also of cemented carbide and the like (Japanese Patent Laying-Open No. 2008-188689 (PTD 3) and Japanese Patent National Publication No. 2008-534297 (PTD 4)).